But on our Alpha Course at St Mary's, in a group comprising a Buddhist, several agnostics and a clutch of Christians, only the confirmed atheist has. Toby, our course leader, has studied the Bible in an academic setting, and appears both wearily surprised and mildly disappointed.

He tells us that the Bible is as unread and misunderstood as A Brief History of Time, a comparison that makes me bristle. We start with a stab at what the Bible is. Is it Harry Potter-esque fiction? Is it Aristotelian morality? Is it history? Well, it's all of those things and more. Its construction is bizarre: epic in narrative, trivial in parts, and trippy in conclusion. How many books tell the same story four times? Toby says we should read it as a whole, in context, and possibly in a group. But who does? In any case, it seems plain to me that if only theologians and biblical scholars can get full understanding and benefit out of the Bible, then we're in real trouble. As Mark Twain said, "It ain't the parts of the Bible that I can't understand that bother me, it is the parts that I do understand."

I have read the whole Bible, and dip in and out of it often, following Don Corleone's maxim about keeping your friends close, but your enemies closer. At school we read it and giggled at the rude bits. As a teenager with mildly dark thoughts, I read it in one go, back to front, as the Omen had piqued my interest in Revelation. All that stuff about the whore of Babylon and the number of the beast is pretty sexy.

We talk a little about the fixing of the canonical Bible during the first centuries AD. We touch on Gnosticism, the Apocrypha and why the Gospel of Thomas is not in the canon. This political history of the Bible is news to the Alpharinos, and we are utterly enthralled, not least because Toby clearly knows his stuff, and is an inspiring teacher.

But alas we have to get back to Christ, as Alpha dictates. We look at various versions of the Bible, and, because I am still very puerile, I giggle at the rude bits. I put my foot in it by referring to 1 Corinthians 13 as a "clichéd wedding speech": someone on the course, inevitably, had it read at their ceremony.

I have no illusions about the divine exquisiteness in the words and message of sections of the Bible, particularly the King James version. Its language permeates our whole culture, and enriches it. Not bad for a bunch of illiterate sheep herders.

But it is also that language with which I have a problem. Because the language of the Bible is culturally ubiquitous, much of its meaning goes unchallenged. The Bible is a mishmash written by hundreds of men over more than a thousand years. And it's been translated and mangled and enhanced over and over again, and fixed in a sort of no man's land somewhere between Jacobean and modern English. Its longevity give it a protective forcefield from neutral criticism because our culture is utterly dependent on it. You can repeat "God is love" until the stars fall from the sky, but I require further explanation. Is that the love that I have for my children, Freddie Flintoff or pepperoni pizza? All are quite profound, but mercifully different.

Funnily enough, Toby doesn't use the standard issue language of Christianity nearly as much as Mike and Bob, the lay church members who help run the course. They talk of "encounters", and "opening your heart" and "walking with Jesus", and "surrendering your wills", and all of the other tropes of Anglicanism that I find so hard to extract meaning from.

Toby suggests that to get the best out of the Bible you have to read it in a particular way. I decide to heed this advice. The hive brain of Alpha, the Holy Trinity Brompton, sent me a leviathan box of Alpha supporting material. "30 Days" by Alpha's architect Nicky Gumbel, is a guide to reading the Bible in the context that Alpha desires. But all I find is glib anecdote – from Geri Halliwell to that key figure for Alpha, CS Lewis – and self help using the same banal banter.

Toby instructs us to "read it expecting that God will talk to you". This is a shameful dodge. Idiosyncratic interpretation of the Bible has resulted in some of the most egregious acts in history. And yet somehow, this is not because of its often hateful, bizarre or contradictory contents. It's our fault because we are reading it wrong. But the truth is that I love reading the Bible, and think, like Toby, that everyone should read it through, given the right context. It spells out how pernicious and weird religion can be, and how beautiful and important compassion is. If you can manage the whole thing without the burden of faith, there is no better guide to being a good humanist.